The U.S. Department of Defense is building its own secure 4G network to improve collaboration among separate branches of the military, according to the chairman of the U.S. Joint Chiefs of Staff.

The network is part of an effort dubbed "Joint Information Environment," which will consolidate 15,000 Defense Department networks in the cloud, Army Gen. Martin Dempsey said in a speech (PDF) delivered Thursday at the Brookings Institute, an influential think tank based in Washington, D.C. In addition to greater collaboration, the new network will be "significantly more secure, helping ensure the integrity of our battle systems in the face of disruption," Dempsey said.

The network, which will allow access to a variety of mobile devices, is expected to be operational by the middle of next year, Dempsey said, as he gave a preview of the type of security to which service people will be privy.

"This phone would make both Batman and James Bond jealous," he said, holding up what he said was a secure mobile phone. "With tools like this, the smartphone generation joining our military will help us pioneer a new era of mobile command and control."

Part of the plan is a federated app store that will allow Defense Department users to share content across several devices, he said.

"By using off-the-shelf technology, we are bringing the full force of the tech revolution into the classified environment," Dempsey said.

Earlier this year, the U.S. Defense Information Systems Agency approved the use of Apple iOS 6 devices, Galaxy S4, and BlackBerry 10 devices by U.S. government and military departments that tap into the Department of Defense networks. The Defense Department currently has more than 600,000 commercial mobile devices in operational and pilot use, including 470,000 BlackBerrys, 41,000 Apple devices, and 8,700 Android devices.

Noting that the U.S. military has made significant progress in embracing the cyber realm, Dempsey echoed previous Defense Department concerns that efforts to protect critical private-sector infrastructure facilities are "lagging."

"Too few companies have invested adequately in cybersecurity. I worry that adversaries will seek to exploit this chink in our nation's armor," the general said. "To them, our economy and infrastructure are softer targets than our military."

Improving battlefield communications infrastructure has been a prominent goal of the Defense Department. The Defense Advanced Research Projects Agency announced last December it was looking for ideas on how to update the military's wireless communications platform to deliver 100Gbps connections.